Data / Rankings / Population under 18 / Counties in Michigan

Counties in Michigan by population under 18

St. Joseph County had the highest population under 18 of 83 counties in 2020, at 24.6%. Ontonagon County had the lowest, at 11.6%. The median was 20% and the figure for Michigan was 21.5%. Source: the U.S. Census Bureau.

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Highest24.6St. Joseph County
Lowest11.6Ontonagon County
Median2083 counties
Michigan21.5History

Map of counties, 2020

Alcona County: 13.3 %Alger County: 15.7 %Allegan County: 24 %Alpena County: 18.5 %Antrim County: 17.3 %Arenac County: 18.3 %Baraga County: 17.4 %Barry County: 22.5 %Bay County: 19.8 %Benzie County: 17.4 %Berrien County: 21.6 %Branch County: 23.9 %Calhoun County: 23 %Cass County: 21.2 %Charlevoix County: 18.4 %Cheboygan County: 17 %Chippewa County: 18.7 %Clare County: 20 %Clinton County: 22.4 %Crawford County: 18.1 %Delta County: 19.5 %Dickinson County: 19.7 %Eaton County: 21.2 %Emmet County: 18.3 %Genesee County: 22.4 %Gladwin County: 18.9 %Gogebic County: 16.6 %Grand Traverse County: 19.8 %Gratiot County: 21.4 %Hillsdale County: 22.1 %Houghton County: 19.8 %Huron County: 18.8 %Ingham County: 20.1 %Ionia County: 21.7 %Iosco County: 17.1 %Iron County: 17.1 %Isabella County: 19.2 %Jackson County: 21.2 %Kalamazoo County: 22 %Kalkaska County: 20.4 %Kent County: 23.8 %Keweenaw County: 15.2 %Lake County: 15.9 %Lapeer County: 20.6 %Leelanau County: 16.2 %Lenawee County: 21 %Livingston County: 21.2 %Luce County: 16.3 %Mackinac County: 16.6 %Macomb County: 20.6 %Manistee County: 16.9 %Marquette County: 18 %Mason County: 20 %Mecosta County: 19.9 %Menominee County: 18.2 %Midland County: 21.5 %Missaukee County: 22.6 %Monroe County: 21.1 %Montcalm County: 21.3 %Montmorency County: 15.4 %Muskegon County: 22.7 %Newaygo County: 22.5 %Oakland County: 20.5 %Oceana County: 22.6 %Ogemaw County: 18.4 %Ontonagon County: 11.6 %Osceola County: 23.4 %Oscoda County: 18.7 %Otsego County: 20.8 %Ottawa County: 23.6 %Presque Isle County: 15.4 %Roscommon County: 14.4 %Saginaw County: 21.9 %St. Clair County: 20.5 %St. Joseph County: 24.6 %Sanilac County: 21.3 %Schoolcraft County: 17.4 %Shiawassee County: 20.9 %Tuscola County: 21.1 %Van Buren County: 23.1 %Washtenaw County: 18.4 %Wayne County: 23.4 %Wexford County: 23.1 %
  • Under 17
  • 17 to 18
  • 18 to 20
  • 20 to 21
  • 21 to 22
  • 22 and over
%, 2020. Source: Invokely calculation with data from U.S. Census Bureau. Boundaries: U.S. Census Bureau cartographic boundary files.

Top 40 counties, 2020

St. Joseph County: 24.6 %St. Joseph County24.6Allegan County: 24 %Allegan County24Branch County: 23.9 %Branch County23.9Kent County: 23.8 %Kent County23.8Ottawa County: 23.6 %Ottawa County23.6Osceola County: 23.4 %Osceola County23.4Wayne County: 23.4 %Wayne County23.4Wexford County: 23.1 %Wexford County23.1Van Buren County: 23.1 %Van Buren County23.1Calhoun County: 23 %Calhoun County23Muskegon County: 22.7 %Muskegon County22.7Missaukee County: 22.6 %Missaukee County22.6Oceana County: 22.6 %Oceana County22.6Newaygo County: 22.5 %Newaygo County22.5Barry County: 22.5 %Barry County22.5Clinton County: 22.4 %Clinton County22.4Genesee County: 22.4 %Genesee County22.4Hillsdale County: 22.1 %Hillsdale County22.1Kalamazoo County: 22 %Kalamazoo County22Saginaw County: 21.9 %Saginaw County21.9Ionia County: 21.7 %Ionia County21.7Berrien County: 21.6 %Berrien County21.6Midland County: 21.5 %Midland County21.5Gratiot County: 21.4 %Gratiot County21.4Montcalm County: 21.3 %Montcalm County21.3Sanilac County: 21.3 %Sanilac County21.3Jackson County: 21.2 %Jackson County21.2Cass County: 21.2 %Cass County21.2Eaton County: 21.2 %Eaton County21.2Livingston County: 21.2 %Livingston County21.2Tuscola County: 21.1 %Tuscola County21.1Monroe County: 21.1 %Monroe County21.1Lenawee County: 21 %Lenawee County21Shiawassee County: 20.9 %Shiawassee County20.9Otsego County: 20.8 %Otsego County20.8Lapeer County: 20.6 %Lapeer County20.6Macomb County: 20.6 %Macomb County20.6St. Clair County: 20.5 %St. Clair County20.5Oakland County: 20.5 %Oakland County20.5Kalkaska County: 20.4 %Kalkaska County20.4St. Joseph County: 24.6 %St. Joseph County24.6Allegan County: 24 %Allegan County24Branch County: 23.9 %Branch County23.9Kent County: 23.8 %Kent County23.8Ottawa County: 23.6 %Ottawa County23.6Osceola County: 23.4 %Osceola County23.4Wayne County: 23.4 %Wayne County23.4Wexford County: 23.1 %Wexford County23.1Van Buren County: 23.1 %Van Buren County23.1Calhoun County: 23 %Calhoun County23Muskegon County: 22.7 %Muskegon County22.7Missaukee County: 22.6 %Missaukee County22.6Oceana County: 22.6 %Oceana County22.6Newaygo County: 22.5 %Newaygo County22.5Barry County: 22.5 %Barry County22.5Clinton County: 22.4 %Clinton County22.4Genesee County: 22.4 %Genesee County22.4Hillsdale County: 22.1 %Hillsdale County22.1Kalamazoo County: 22 %Kalamazoo County22Saginaw County: 21.9 %Saginaw County21.9Ionia County: 21.7 %Ionia County21.7Berrien County: 21.6 %Berrien County21.6Midland County: 21.5 %Midland County21.5Gratiot County: 21.4 %Gratiot County21.4Montcalm County: 21.3 %Montcalm County21.3Sanilac County: 21.3 %Sanilac County21.3Jackson County: 21.2 %Jackson County21.2Cass County: 21.2 %Cass County21.2Eaton County: 21.2 %Eaton County21.2Livingston County: 21.2 %Livingston County21.2Tuscola County: 21.1 %Tuscola County21.1Monroe County: 21.1 %Monroe County21.1Lenawee County: 21 %Lenawee County21Shiawassee County: 20.9 %Shiawassee County20.9Otsego County: 20.8 %Otsego County20.8Lapeer County: 20.6 %Lapeer County20.6Macomb County: 20.6 %Macomb County20.6St. Clair County: 20.5 %St. Clair County20.5Oakland County: 20.5 %Oakland County20.5Kalkaska County: 20.4 %Kalkaska County20.4
%. Source: Invokely calculation with data from U.S. Census Bureau. Retrieved 2026-10-12.

Full ranking

RankCounties2020 (%)Change on 2019
1St. Joseph County24.6+0.2 pts
2Allegan County24-0.2 pts
3Branch County23.9-0.1 pts
4Kent County23.8-0.1 pts
5Ottawa County23.6-0.3 pts
6Osceola County23.4+0.2 pts
7Wayne County23.40 pts
8Wexford County23.10 pts
9Van Buren County23.1-0.1 pts
10Calhoun County23+0.1 pts
11Muskegon County22.7+0.1 pts
12Missaukee County22.6-0.3 pts
13Oceana County22.6-0.3 pts
14Newaygo County22.50 pts
15Barry County22.5-0.3 pts
16Clinton County22.4-0.4 pts
17Genesee County22.4+0.1 pts
18Hillsdale County22.1-0 pts
19Kalamazoo County22-0 pts
20Saginaw County21.9-0.1 pts
21Ionia County21.70 pts
22Berrien County21.60 pts
23Midland County21.5-0.2 pts
24Gratiot County21.4-0.3 pts
25Montcalm County21.3-0.2 pts
26Sanilac County21.3-0.3 pts
27Jackson County21.2-0 pts
28Cass County21.2-0.2 pts
29Eaton County21.2-0.2 pts
30Livingston County21.2-0.4 pts
31Tuscola County21.1-0.2 pts
32Monroe County21.1-0.2 pts
33Lenawee County21-0 pts
34Shiawassee County20.9-0.1 pts
35Otsego County20.8+0.4 pts
36Lapeer County20.6-0.3 pts
37Macomb County20.6-0 pts
38St. Clair County20.5-0.1 pts
39Oakland County20.5-0.2 pts
40Kalkaska County20.4+0.2 pts
41Ingham County20.1+0.1 pts
42Clare County20-0.2 pts
43Mason County200 pts
44Mecosta County19.9-0.2 pts
45Bay County19.8-0.1 pts
46Houghton County19.8-0.3 pts
47Grand Traverse County19.8-0 pts
48Dickinson County19.7-0.2 pts
49Delta County19.50 pts
50Isabella County19.2+0.2 pts
51Gladwin County18.90 pts
52Huron County18.8-0.2 pts
53Oscoda County18.7+0.9 pts
54Chippewa County18.7+0.2 pts
55Alpena County18.5-0.2 pts
56Ogemaw County18.4-0.2 pts
57Washtenaw County18.4-0.1 pts
58Charlevoix County18.4-0.3 pts
59Emmet County18.3-0.2 pts
60Arenac County18.3+0.4 pts
61Menominee County18.2-0.2 pts
62Crawford County18.1-0.1 pts
63Marquette County18-0.2 pts
64Schoolcraft County17.4+0.2 pts
65Baraga County17.4-0.1 pts
66Benzie County17.4-0.2 pts
67Antrim County17.3-0.4 pts
68Iosco County17.1-0 pts
69Iron County17.1+0.1 pts
70Cheboygan County17-0.4 pts
71Manistee County16.9-0.1 pts
72Gogebic County16.6-0.1 pts
73Mackinac County16.6+0.1 pts
74Luce County16.3-2.6 pts
75Leelanau County16.2-0.3 pts
76Lake County15.9-0 pts
77Alger County15.7+0.3 pts
78Presque Isle County15.4-0 pts
79Montmorency County15.4+0.1 pts
80Keweenaw County15.2+0.5 pts
81Roscommon County14.4-0 pts
82Alcona County13.3+0.4 pts
83Ontonagon County11.6-0.6 pts

Other periods

About this ranking

Residents aged 0 to 17 as a percentage of total population on 1 July. United States: Census Bureau county population estimates by age; states and the nation are sums of their counties.

Uses the US age of majority. Not comparable with population_0_14_share, which stops at 14.

Every value in the ranking comes from the same publisher and the same period, so the counties are compared on one definition. Equal values share a rank.

How to cite

U.S. Census Bureau. Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Retrieved 2026-10-12.

Citation styles

The publisher is the author. Invokely is named only as the place the figures were read, where a style asks for it.

APA 7

U.S. Census Bureau. (2026). Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties (Counties in Michigan by population under 18, 2020) [Data set]. Retrieved October 12, 2026, from https://www.census.gov/programs-surveys/popest/data/data-sets.html

MLA 9

Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties, Counties in Michigan by population under 18, 2020. U.S. Census Bureau, 25 June 2026, https://www.census.gov/programs-surveys/popest/data/data-sets.html. Invokely, https://invokely.ai/rankings/population-under-18/michigan-counties?period=2020. Accessed 12 Oct. 2026.

Chicago (author-date)

U.S. Census Bureau. 2026. Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. Counties in Michigan by population under 18, 2020. Dataset. Accessed October 12, 2026. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Also distributed by Invokely, https://invokely.ai/rankings/population-under-18/michigan-counties?period=2020.

Harvard

U.S. Census Bureau (2026) Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties, Counties in Michigan by population under 18, 2020 [Dataset]. Available at: https://www.census.gov/programs-surveys/popest/data/data-sets.html, via Invokely: https://invokely.ai/rankings/population-under-18/michigan-counties?period=2020 (Accessed: 12 October 2026).

BibTeX
@misc{census_counties_in_michigan_by_2020,
  author = {{U.S. Census Bureau}},
  title = {{Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties: Counties in Michigan by population under 18, 2020}},
  year = {2026},
  howpublished = {Data set},
  url = {https://www.census.gov/programs-surveys/popest/data/data-sets.html},
  urldate = {2026-10-12},
  note = {Accessed via Invokely, https://invokely.ai/rankings/population-under-18/michigan-counties?period=2020. Publisher attribution: U.S. Census Bureau. Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Retrieved 2026-10-12.},
}
RIS
TY  - DATA
AU  - U.S. Census Bureau
TI  - Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties: Counties in Michigan by population under 18, 2020
PY  - 2026
DA  - 2026/06/25
PB  - U.S. Census Bureau
DB  - Invokely
UR  - https://www.census.gov/programs-surveys/popest/data/data-sets.html
L2  - https://invokely.ai/rankings/population-under-18/michigan-counties?period=2020
Y2  - 2026/10/12
N1  - Accessed via Invokely, https://invokely.ai/rankings/population-under-18/michigan-counties?period=2020.
N1  - Publisher attribution: U.S. Census Bureau. Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. https://www.census.gov/programs-surveys/popest/data/data-sets.html. Retrieved 2026-10-12.
ER  -
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Rank Counties in Michigan by population under 18 using official data, and cite the source.
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Questions

Which county has the highest population under 18?

St. Joseph County, with 24.6% in 2020, according to the U.S. Census Bureau.

Which county has the lowest population under 18?

Ontonagon County, with 11.6% in 2020.

Where does this ranking come from?

Every value comes from one source and one period, so the places are comparable: U.S. Census Bureau, Population Estimates Program, county population by age and sex: residents aged 0 to 17 as a percentage of the total on 1 July, 2010 to 2019 from the 2010 to 2020 intercensal file and 2020 onwards from the latest vintage; states and the nation summed from counties. Retrieved 2026-10-12.

Population under 18: other rankings

Counties in Michigan: more rankings